The present invention concerns a procedure for affixing bearing hoops on the outer surface of a barking drum or another similar large diameter drum, said bearing hoops resting on carrier wheels thereunder, by the aid of which the drum is rotated, in which procedure the drum is provided with an open longitudinal seam, the bearing hoops and the carrier wheels are initially properly positioned with reference to each other.
The invention concerns particularly barking drums, but it may also be applied to other large diameter drums used for instance in the concrete, lime, cellulose and metallurgic industries. Drums such as these are characterized by a massive construction, in which the diameter may be 3 to 6 meters, the length 25 to 40 meters and the thickness of the drum shell 30 to 60 millimeters.
In drums of this type, the affixing of the bearing hoops to the drum shell has caused great difficulties. The shifting stress and deformation wave caused by the rotational movement of the drum and by the carrier wheels has given rise to fatigue problems concerning the attachment in those problem solutions that have been applied. This has occurred in the case both of bolted and welded bearing hoops, in which in both instances there is produced a destructive pulsating tension load acting on the juncture between the drum and the bearing hoop. As a result of such pulsating loads, bolts can break and welded joints crack open. These prior art methods of attachment have the further drawback of poor contact between the bearing hoop and the carrier wheel.
Bearing hoops have also been affixed by means of wedging, the wedges being driven in between the bearing hoop and the drum. This procedure has the advantage of a good contact surface between the wheels and the hoop, but its essential drawback is loosening of the wedges in the course of time.